A RBT is a sound played by a network communication system to a calling party when the calling party calls a called party, and the RBT is generally a section of beeps in earlier. A Color Ring Back Tone (CRBT) service means that, when a calling party calls a called party and the called party is successfully paged and rings, the calling party may hear an RBT pre-customized by the called party, the calling party or the third party instead of default beeps. The RBT may be music, songs or voices. The CRBT service is applicable to not only a mobile communication network, but also a fixed communication network.
Along with the establishment of 3rd Generation mobile communication system Release 4 (3G R4), 3G R5 and Next Generation Network (NGN), a communication network is able to support a multimedia service, and a CRBT service is extended to a Multimedia Ring Back Tone (MRBT) service. The MRBT service means that, when a calling party calls a called party, after the called party is successfully paged and rings, the calling party may receive and play multimedia contents consisting of video and audio pre-customized by the called party, the calling party or the third party. Correspondingly, the original customized RBT service is termed as a voice CRBT service. Since the implementation of MRBT service is more complex than that of voice CRBT service, an existing voice CRBT service system can not be directly used for implementing the MRBT service.